There have been developed many particular chemical substances for the prevention and treatment of cancer. Representative examples of such anti-cancer substances include vitamin A (retinol) and retinoids. U.S. Pat. No. 4,310,546 discloses N-(4-acyloxyphenyl)-all-trans-retinamide, U.S. Pat. No. 4,323,581 discloses N-(4-hydroxyphenyl)-all-trans-retinamide, and U.S. Pat. No. 4,665,098 discloses N-(4-hydroxyphenyl) retinamide known as fenretimide.
Retinoids are involved in cell differentiation and individual development by binding to RAR(retinoic acid receptor) or RXR(retinoid X receptor), which exist in a nucleus of a cell, to assist transcriptional activity of RAR/RXR. These compounds are known to exert anti-cancer effects by indirectly interacting with the transcriptional activator, AP-1(activation protein-1) and inhibiting activity of-AP-1 to prevent the expression of a target gene of AP-1, which is involved in the development and metastasis of cancer (Yang-Yen H. F., et al., New Biol. 3:1206–1219, 1991). It is also known that retinols and retinoids suppress imprudent proliferation of cells and induce differentiation or apoptosis and thus will be potentially used for the prevention and treatment of cancer (Hong W. K. and Itri L. M., Biol. Chem. Med., 2nd ed. edited by Sporn et al., New York: Raven Press; 597–630, 1994). However, the therapeutic use of retinoids has been restricted because these compounds would be accompanied by undesirable side effects, for example skin irritation, toxication on organis, and deformation of organs, occurred by some of proteins activated by binding retinoids to their receptors, (Hathcock J. N., et al., Am. J. Clin. Nutr., 52, 183–202, 1990).
Recently, several retinoid derivatives have been found to exhibit improved anti-cancer efficacy over prior retinoids but show reduced side effects. U.S. Pat. No. 6,117,845 discloses anti-cancer compounds represented by the formula:
Also, U.S. Pat. No. 6,274,742 discloses N-homocysteine thiolactonyl retinamide compounds represented by the formula:

Some of the foregoing compounds are demonstrated to have relatively excellent anti-cancer effects with low side effects and are under clinical trials. Such representative examples include N-(4-hydroxyphenyl)-all-trans-retinamide compounds. However, even N-(4-hydroxyphenyl)-all-trans-retinamide compounds do not fulfill requirements for a anti-cancer drug in that these compounds stimulate tissues when being orally administered at a high dose, which would be an inherent problem of retinoid family drugs.